Phonograph-transmitter



Patented June 21, 1921.

I (2 96199176 fiflz/s.

GREGG K. MILLS,

OF CHICAGO, ILLINOIS.

PHONOGBAPH-TRANSMITTEB.

Specification of Letters Patent.

Patented June 21, 1921.

Application filed May 28, 1919. Serial No. 300,456.

To an whom it may concern:

Be it known that I, Gnnco K. MILLs, citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new an useful Improvement in Phonograph-Transmitters, of which the following is a full, clear, concise, and exact description.

My invention relates to sound recording and sound reproducing machines, herein generically termed phonographs, and par- 'cularly to the transmitter portions there'- of which employ diaphragms and also styluses which are either operated by or operate transmitter diaphragms according to whether the phonographs are sound recording or sound reproducing machines.

My invention resides in a structure for improving the vibration transmitting function of a phonograph transmitter diaphragm.

The structure of my invention includes a diaphragm whose rim is formed with spaced apart rims which are desirably of unequal radial length and preferably of two different vibrant materials, one rimportion being of the same material as the undivided portion of the diaphragm.

The accompanying drawing shows the preferred embodiments of the structure of my invention.

Figure 1 is a side View of a transmitter made in accordance with the inventon; Fig. 2 is a sectional view on line 2-2 of Fig. 1; and Fig. 3 is a detail sectional view taken on a diametrical line of the transmitter diaphragm.

Like parts are indicated by similar charactors of reference throughout the different figures.

The transmitter casing 1 is shown u on the tone arm 2, which is but partially il ustrated. The interior of this casing is sufficiently deep to permit the vibrant transmitter diaphragm 3 to be disposed therein in spaced apart relation to the contiguous end of the tone arm whose interior is in communication with the casing. The diaphragm preferably has a vibrant rim or peripheral portion 4 which is homogeneous with, though desirably thinner than, the central portion of the diaphragm. A peripheral vibrant ortion 5 desirably of different material an preferably of greater radial length is secured to the balance of the diaphragm in any suitable way. The parts 45 and 5 diverge outwardly to permit the part 5 to be sinuous in formation to increase its radial length. When the part 5 is thus formed, a cushion or gasket 6, of rubber or other suitable material, is interposed between the parts 4 and 5 yieldingly to maintain them in spaced apart relation. A similar gasket 7 is interposed between the bottom of the casing 1 and the diaphragm rim ort-ion 4, which is preferably innermost.

A third gasket 8 is interposed between the diaphragm rim portion and the retaining ring 9 which may be secured to the casing by screws 10. This ring places the cushioning gaskets under sufficient pressure maintain them and the diaphragm rims interposed therebetween in proper assembly with the casing. The balance of the structure, inclusive of the stylus bar 11 and the stylus holder 12, are well known and require no description in particular.

As hitherto stated, the diaphragm rim portion 5 is radially longer than the rim portion 4, particularly if it should be made of the same material with the balance of the diaphragm. It is also preferably thinner than the rim portion 4. In the preferred embodiment of the invention, the rim portion 5 is of different material fromv the balance of the diaphragm and whileboth rim portions 4 and 5 serve to propagate vibrations at a high rate, yet the rate of propagation afforded by one rim portion is low relatively to the other by reason of the different materials of which they are formed or their different lengths or a combination of both of these characteristics. If these rim portions be of the same material the waves being reflected by the rim portions are brought out of phase because of the difference in rims. Different materials for the rim portions is also preferred, however, since the waves being propagated thereover are noncoincident on their outward travel as well as on their reflected movement. In the preferred embodiment of the invention the entire diaphragm structure is made of celluloid. The main part of the diaphragm an the rim portion 4 integral therewith may be impregnated with carborundum to give the same a higher propagation rate than, the rim portion 5 which may be im regnated with chalk sufficiently to reduce its propagation rate in comparison with that of the rim portion 4. The invention, however, is not to be limited to a diaphragm whose rim portions serve to propagate sound Waves at different rates.

While 1 have herein shown the preferred device embracing the invention, I do not Wish to be limited thereto.

I claim:

phragm carried by the casing, phragm having two vibrant spaced apart rims, one of greater radial length than the other. I

2. A transmitter for phonographs including a transmitter casing and a vibrant diaphragm carried by the casing, said dia phragm having two vibrant spaced apart rims, one of greater radial length and of different vibrant material and affording a different rate of Wave propagation than the other.

3. A transmitter for phonographs including a transmitter casing and a vibrant diaphragm carried by the casing, said dia phragm having two vibrant spaced apart rims of different material affording difi'erent rates of wave propagation.

4. A' transmitter for phonographs including a transmitter casing and a vibrant diaphragm carried 10 the casing, said di phragm having two vibrant rims of diifere 't material afl'ording' different rates of wave propagation.

5. A transmitter for phonographs including a transmitter casing and a vibrant diaphragm carried by the casing,' said diaphragm having two spaced apart vibrant rims having different rates of wave propagation.

6. A transmitter for phonographs including a transmitter casing and a vibrant diaphragm carried by the casing, said diaphragm having two vibrant rims having different rates of wave propagation.

A transmitter for phonographs including a transmitter casing and a vibrant diaphragm carried by the casing, said diaphragm having two vibrant rims, one of greater radial length than the other.

In witness whereof,- I hereunto subscribe my name this fourteenth day of May, A. D., 1919.

GREGG K. MILLS. 

